Remove quota feature (incompatible with ZFS-backed LXC)

Linux setquota/repquota require quota support on the underlying
filesystem. The target deployment is a Proxmox LXC on ZFS storage where
this is not available inside the container.

Removed: /api/quota endpoint, _quota_supported, _quota_usage,
_find_quota_fs, quotas.js, quota modal, dashboard quota table,
Quota button from share rows.

PLANNING.md updated: notes quota as out of scope with reason.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.py

@@ -415,58 +415,6 @@ def toggle_nfs():
     return jsonify({'status': 'enabled' if enabled else 'disabled'})
 
 
-# ===== QUOTA =====
-
-def _find_quota_fs(path):
-    """Return the best filesystem argument for setquota.
-
-    setquota needs a path whose filesystem has quota enabled.  We try the
-    exact path first, then walk up to the mountpoint reported by df.  If df
-    says '/' we still try the path itself — the user may have quota on root.
-    """
-    r = subprocess.run(['df', '--output=target', path], capture_output=True, text=True)
-    lines = [l.strip() for l in r.stdout.strip().splitlines()
-             if l.strip() and l.strip() != 'Mounted on']
-    return lines[0] if lines else path
-
-
-@app.route('/api/quota', methods=['POST'])
-@require_auth
-def set_quota():
-    data = request.json or {}
-    user = data.get('user', '')
-    raw_quota = data.get('quota', 0)
-    path = data.get('path', '/srv')
-
-    if not VALID_NAME.match(user):
-        return jsonify({'error': 'invalid username'}), 400
-    try:
-        quota_gb = int(raw_quota)
-        if quota_gb <= 0:
-            raise ValueError()
-    except (ValueError, TypeError):
-        return jsonify({'error': 'quota must be a positive integer (GB)'}), 400
-
-    try:
-        safe_path = validate_path(path)
-    except ValueError as e:
-        return jsonify({'error': str(e)}), 400
-
-    mount = _find_quota_fs(safe_path)
-    soft_kb = str(quota_gb * 1024 * 1024)
-    hard_kb = str((quota_gb + 1) * 1024 * 1024)
-    try:
-        r = subprocess.run(
-            ['setquota', '-u', user, soft_kb, hard_kb, '0', '0', mount],
-            capture_output=True, text=True,
-        )
-        if r.returncode != 0:
-            return jsonify({'error': r.stderr.strip() or 'setquota failed'}), 500
-    except FileNotFoundError:
-        return jsonify({'error': 'setquota not found — install quota package'}), 500
-    return jsonify({'status': 'ok'})
-
-
 # ===== USERS =====
 
 def _smb_users():
@@ -613,64 +561,15 @@ def _shares_with_usage():
     return result
 
 
-def _quota_supported():
-    """Return (supported: bool, reason: str). Checks filesystem type under /srv."""
-    r = subprocess.run(['df', '-T', '/srv'], capture_output=True, text=True)
-    for line in r.stdout.splitlines()[1:]:
-        parts = line.split()
-        if len(parts) >= 2:
-            fstype = parts[1].lower()
-            if fstype == 'zfs':
-                return False, 'ZFS storage detected — Linux disk quotas are not available inside a ZFS-backed container. Manage per-dataset quotas from the Proxmox host with: zfs set quota=10G <dataset>'
-            if fstype in ('tmpfs', 'overlay', 'aufs'):
-                return False, f'{fstype} filesystem does not support disk quotas'
-    return True, ''
-
-
-def _quota_usage():
-    try:
-        r = subprocess.run(['repquota', '-u', '/srv'], capture_output=True, text=True, timeout=10)
-    except FileNotFoundError:
-        return []
-
-    quotas = []
-    past_sep = False
-    for line in r.stdout.splitlines():
-        if line.startswith('---'):
-            past_sep = True
-            continue
-        if not past_sep:
-            continue
-        parts = line.split()
-        if len(parts) < 5 or not re.match(r'^[+-]{2}$', parts[1]):
-            continue
-        try:
-            used_kb, soft_kb, hard_kb = int(parts[2]), int(parts[3]), int(parts[4])
-        except (ValueError, IndexError):
-            continue
-        if soft_kb == 0 and hard_kb == 0 and used_kb == 0:
-            continue
-        quotas.append({
-            'user': parts[0],
-            'used_gb': round(used_kb / 1024**2, 2),
-            'soft_gb': round(soft_kb / 1024**2, 2),
-            'hard_gb': round(hard_kb / 1024**2, 2),
-            'percent': round(used_kb / soft_kb * 100, 1) if soft_kb else 0,
-        })
-    return quotas
 
 
 @app.route('/api/dashboard', methods=['GET'])
 @require_auth
 def get_dashboard():
-    quota_ok, quota_reason = _quota_supported()
     return jsonify({
         'status': _daemon_status(),
         'disk': _disk_usage(),
         'shares': _shares_with_usage(),
-        'quotas': _quota_usage() if quota_ok else [],
-        'quota_supported': quota_ok,
-        'quota_reason': quota_reason,
     })